(a) Technical Field
The present invention generally relates to a dual lumen cannula configured to relieve pressure at an injection site during injection of a fluid into a subject. In particular aspects, the present invention relates to a cannula having a first lumen configured to inject a fluid into a subject and a second lumen configured to divert fluid pressure away from the injection site via a plurality of openings in the cannula.
(b) Background Art
During some forms of surgery, a fluid may be injected into a subject that results in a buildup of fluid pressure at the injection site. For example, in eye surgery, a fluid-like balanced salt solution (BSS) may be injected into the eye before a second fluid is injected, such as a staining dye or perfluorocarbon liquid. Structurally, a human eye is semi-rigid in nature meaning that injection of a fluid into an eye will also cause an internal fluid pressure to form in the eye. Generally speaking, it is considered unsafe for an eye to have a high internal pressure for an extended period of time.
In addition to the potentially unsafe buildup of internal pressure at an injection site, an axial fluid “jet” effect may occur with some cannula designs. In particular, fluid injected through a cannula having an open end (i.e., through an opening at the very tip of the cannula) may cause an axial jet effect condition. For example, a jet effect may occur during eye surgery when a fluid is injected through an open-ended cannula close to the surface of the retina. The resulting jet effect can damage the retina by causing a perforation in the retina via the fluid stream and result in fluid being unintentionally injected under the retina.
Accordingly, there is a demand for the development of improved cannula designs that reduce and/or eliminate the presence of conditions that may cause damage to the injection site and surrounding areas during injection of a fluid.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.